It is well known that color photographic light-sensitive materials, using the subtractive process for color reproduction, comprise silver halide emulsion layers selectively sensitive to blue, green and red light and associated with yellow, magenta and cyan dye forming couplers which (upon reaction with an oxidized primary amine type color developing agent) form the complementary colors. For example, an acylacetanilide type coupler is used to form a yellow color image; a pyrazolone, pyrazolotriazole, cyanacetophenone or indazolone type coupler is used to form a magenta color image; and a phenol type, such as a phenol or naphthol, coupler is used to form a cyan color image.
Usually, the color photographic light-sensitive materials comprise non-diffusible couplers incorporated independently in each of the light-sensitive layers of the material (incorporated coupler materials). Therefore, a color photographic light-sensitive material usually comprises a blue-sensitive silver halide emulsion layer (or layers) which contains a yellow coupler and is sensitive mainly to the blue light (substantially to wavelenghts less than about 500 nm), a green-sensitive silver halide emulsion layer (or layers) which contains a magenta coupler and is sensitive mainly to green light (substantially to wavelengths of about 500 to 600 nm) and a red-sensitive silver halide emulsion layer (or layers) which contains a cyan coupler and is sensitive mainly to red light (substantially to wavelengths longer than about 590 nm).
It is also known to incorporate into a ligh-sensitive color photographic material a compound capable of releasing a development inhibitor during development upon reaction with the oxidation product of a color developing agent. Typical examples of said compounds are the DIR (Development Inhibitor Releasing) couplers having a group having a development inhibiting property when released from the coupler itself. These groups are introduced in the coupling position of the coupler. Examples of DIR couplers are described by C. R. Barr, J. R. Thirtle and P. W. Wittum, Photographic Science and Eng., vol. 13. pp 74-80 (1969) and ibid. pp 214-217 (1969) or in U.S. Pat. Nos. 3,227,554, 3,615,506, 3,617,291, 3,701,783, 3,933,500 and 4,149,886.
The purpose of DIR couplers is to reduce grainines and improve sharpness of the image due to intralayer (or intraimage) effects and improve color reproduction due to interlayer (or interimage) effects. Usually, however, the DIR coupler causes, in the light-sensitive emulsion layer in which it is used, a strong development-restraining effect upon development which reduces maximum color density (Dmax) and a lowering of the sensitivity. Therefore, in order to more effectively use the DIR couplers, it is desirable to develop novel DIR couplers which reduce maximum color density (Dmax) and sensitivity to a lesser extent and provide an improved image quality.
Several substituents on the phenyl ring of the 1-phenyl-tetrazolyl-5-thio development inhibiting group of DIR couplers have been described, for example in DE patent applications Nos. 2,454,301 and 2,454,329 and in BE Pat. No. 789,595. Among these, a CF.sub.3 substituent has been described in BE patent 789,595 in phenolic or naphtholic couplers for use as cyan dye forming DIR couplers.